Various kinds of wigs or hairpieces whose bases are formed by networks are well known. One of these wig bases is known, for example, from the wig base manufacturing method disclosed in Japanese Patent Preliminary Publication No. Sho 61-124615 laid open to public inspection on June 12, 1986 and filed by the same applicant as that of the present application. According to this wig base manufacturing method, the wig base is formed by applying a special shaping treatment to its network to insure that the wig can keep its contour and dimension in strict agreement with the shape of the head of the wearer or user on which the wig is to be placed. This makes it more difficult for the wig base to be deformed, even after it is used for a long time. However, no attempt is made to make the front edge portion of the wig base (which is located at the hairline on the user's forehead) look natural.
In the case of a wig whose base is formed by a network, a fringing ribbon or tape is stitched or stuck along the inner surface of the peripheral edge of the network so as to reinforce the same and to conform the entire wig to the contour of the user's head which is to be covered by the wig. In wigs of the so-called "hard front" type, this fringing ribbon or tape is stitched to the inner surface of the front edge portion of the wig base which corresponds to the hairline portion on the user's forehead, so that the front edge portion of the wig is prevented from floating from the user's forehead.
If this reinforcement technique of stitching or sticking the fringing ribbon or tape to the wig base is applied to the wig base which is made according to the method disclosed in Japanese Patent Preliminary Publication No. Sho 61-124615, the wig thus formed keeps its shape more effectively and is more durable. However, in those wigs adapted for brush-back hair styles, those hairs which have been attached to the outer surface of the front edge portion of the wig base are combed rearwardly from the hairline at the front edge portion of the wig base. Therefore, the fringing ribbon or tape which has been stitched or stuck to the inner surface of the front edge portion of the wig base is exposed thereby creating a visual indication of the presence of the wig.
In order to overcome this problem, a wig or hairpiece of the so-called "lace front" type is disclosed in U.S. Pat. No. 4,509,539, for example. In the case of this wig, the entire wig base is constituted by a network of lace meshes wherein a plurality of filaments cross one another and are ultrasonically welded at their intersections so as to form a mesh. Therefore, this network of lace meshes is not fringed at the front edge portion thereof and the wig of this type thus exhibits a hairline whereby the hairs appear to be growing directly from the user's scalp at his forehead area. Even in the case of brush-back hair styles, therefore, the border between the user's forehead and the front edge portion of the wig can certainly provide a natural hairline, but this wig or hairpiece has other drawbacks. For example, the network of those filaments which form the front edge portion of the wig base is ultrasonically welded at the intersections of the filaments, but is not fringed at its front edge portion. Accordingly, the shape-retainability of the network is low as compared with the above-described hard front type. Secular change or distortion causes the wig to lose its shape and become deformed. Clearances are thus created between the user's forehead and the front edge portion of the wig base, thereby causing the front edge portion to be curled up or bent under itself and sometimes causing the filaments, which form the front edge portion of the wig base, to become visible due to the front edge portion of the wig base floating from the user's forehead. When this wig is used for a long period of time, those filaments which form the wig base along the front edge portion thereof are parted from one another at some of their welded intersections and some of those filaments which form the unreinforced network are broken, thereby making it more likely that the network will become loose at the front edge portion of the wig base. The deformation of the wig base and the loosening of the network at the front edge portion thereof are often caused when the hair is brushed, washed and carelessly treated, thereby reducing the wig's durability. On the other hand, wigs of the lace mesh type are comprised of a network as a whole. In the case where a hair-parting line is formed on the wig, therefore, the filaments which form the network are exposed at this hair parting line where the user's own skin should appear, thereby visually indicating the presence of the wig.
If a hair whirl is to be formed on the wig, hair fibers which are planted on the surface of the wig base must have a higher density at an area where the hair whirl is formed, than at the remaining area. When they are planted, the hair fibers must also be directed in clockwise or counterclockwise direction in a spirally extending manner. In a case where the hair whirl is to be formed on the wig which is made by a network according to U.S. Pat. No. 4,509,539, however, the planted hair fibers cannot be increased in number because the network is formed in a rectangular mesh having constant intervals. Further, since the hair fibers are tied to those filaments which form the rectangular mesh, they have a lattice pattern when thus planted, thereby making it difficult to form a spiral pattern. Still further, each of the hair fibers which have been tied to the filaments is shifted from its original position and direction by hair brushing or the like. It is therefore difficult with the wig disclosed in U.S. Pat. No. 4,509,539 to maintain the planted hair fibers in a uniform direction, thereby making it impossible to form hair whirls.
Furthermore, in order to make the hairline look natural at the front edge portion of the wig base, it is more preferable that the hair fibers to be planted at the front edge portion are tied thereto at appropriate intervals and at random rather than in linear and close alignment. If meshes are rough at the front edge portion of the wig base, however, the tied hair fibers are limited in number and position, thereby making it difficult to provide a random and natural hairline.